Aquaplan project

A stochastic approach to analyze trade-offs and risks associated with large-scale water resources systems

by Amaury Tilmant¹, Rapahel Kelman²

 ¹ Department of Management and Institutions, UNESCO-IHE, Delft, The Netherlands
Department of Environmental Sciences and Land Use Planning, Universite catholique de Louvain, Louvain-la-Neuve, Belgium

² Power System Research, Rio de Janeiro, Brazil 

Abstract. Water resources development projects often involve multiple and conflicting objectives as well as stochastic hydrologic inputs. Multiobjective optimization techniques can be used to identify non-inferior solutions and to construct a trade-off relationship between conflicting objectives. This paper presents a methodology for analyzing trade-offs and risks associated with large-scale water resource projects under hydrologic uncertainty. The proposed methodology relies on the stochastic dual dynamic programming (SDDP) model to derive monthly or weekly operating rules for multipurpose multireservoir systems taking into account the stochasticity of the inflows, irrigation water withdrawals, minimum/maximum flow requirements for navigation, fishing and/or for ecological purposes. In SDDP, release decisions are chosen so as to minimize the operating costs of a hydrothermal electrical system. Irrigation water demands and other  operating constraints are imposed on the system through the SDDP model. The proposed methodology is illustrated with the Southeastern Anatolia Development project, commonly called GAP, in Turkey. The GAP is a multidimensional development project  involving primarily the production of hydroelectricity and irrigation. Simulation results  using 50 hydrologic scenarios show that the complete development of the irrigation projects  would reduce the total energy output by 6.5%, and will incease the risk of not meeting  minimum outflow at the Syrian border from 5% to 25%.